The invention relates to a high-pressure coupling device for directing media through quick-change systems.
Such a high-pressure coupling device became known for example with EP 1 050 363 A2, which goes back to the same inventor. The invention's field of application refers to all high-pressure coupling devices for directing a high-pressure medium, for example such as oil, water, gas, fats and similar media. The inventive high-pressure coupling device is therefore applicable for all quick-change systems, in particular for quick-change systems in processing machines, however also for quick-change systems for example such as the coupling of a dredging shovel to a post and similar devices.
Thus the invention is not limited to the description of a high-pressure coupling device in connection with a quick-change system with the help of a work-piece pallet and one or more rapid-action clamping cylinders arranged in the machine table.
In the initially mentioned EP 1 050 363 A2 the high-pressure coupling device was arranged directly in the cover of a rapid-action clamping cylinder embedded in the machine table. However, with this there was the disadvantage that only a severely limited installation space was given for the high-pressure coupling device, because it was integrated in the small-size cover of a conventional rapid-action clamping cylinder. Only slight openings could be achieved and the rate of flow per time unit was thus severely restricted.
Additionally the pressure range was limited to only about 150 bar maximum, because with higher pressures and higher rates of flow a forced closing of the valve resulted because the existing spring restricted the maximum pressure.
It was a matter of a single-sided acting valve which permitted a high rate of flow in the one direction, but permitted only a low rate of flow in the other direction. If the rate of flow in the reverse direction was exceeded, the valve closed.
In other respects, in the case of higher pressures it turned out that the valve case bulged out over the surface of the cover of the quick-clamping cylinder in undesirable manner, which resulted in leakage and high pressure-oil loss.
The top side of the valve body thus bulged out over the surface of the cover of the rapid-action clamping cylinder, as a result of which a flat rest of the workpiece pallet that is to be placed with high precision on the rapid-action clamping cylinder was no longer given. As a result of this the entire system warped.
Due to the repeated distortion of the oil flow in the case of the known system there were friction losses and an unintentional heating up of the valve in the case of media flowing through at a high rate of speed.
Due to the unintentional heating up of the valve at high rates of flow the entire rapid-action clamping system warped, which led to an inaccuracy in the processing of the workpieces clamped on to the workpiece pallet.
With the use of quick-switching solenoid valves in medium flow there was the further disadvantage that as a result of the switching impacts that were transferred to the medium the valve body in the known valve clogged up and blocked in terms of a self-closing.
In the case of such an oil impact it could also happen that the valve body in the top part was brought into an on position in undesirable manner, as a result of which the seal between the top and bottom parts was terminated and a lateral pressure oil loss took place.